Scientists detonate underground bombs in California for earthquake research

"To study California's fault lines, researchers recently detonated explosives underground to create 3D models of seismic activity; a team of geologists and seismic experts travelled to areas in the Imperial and Coachella Valley, roughly 150 miles northeast of San Diego, California, to study the southern tip of the San Andreas Fault; a team detonated more than 120 explosives more than sixty feet deep to set off seismic waves; the team measured these wave patterns with 3,000 different sensors to create a 3D map in these fault areas; their work comes as part of the Salton Seismic Imaging Project."